Process for treating cellulose material with thermoplastic material and product thereof



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' This invention relates to the treatment of cellulosic containing textile materials and more preferably cotton containing textile material with a composition comprising as essential components a thermosetting aminoplast resin and a thermoplastic copolymer latex in which the said components are present in critical amounts and in which the thermoplastic copolymer is of critical composition.

The concept of treating cellulosic textile materials with water-soluble aminoplast resins, as for example, methylated methylol melamine resins, is known and described in US. Patent No. 2,339,203, and it has also been suggested in the prior art that textile materials including cotton textile materials be impregnated with various thermoplastic materials, among which are polymeric esters of unsaturated aliphatic acids, as for example, polymeric methyl acrylate.

In addition, in US. Patent No. 2,536,050, the combination of thermoplastic copolymers and thermosetting resins, have been suggested for use in the treatment of textile materials for purposes of imparting superior crease resistance, abrasion resistance, and the like thereto. While, for the most part, the compositions described in U.S. Patent 2,536,050 are suitable, certain limitations have been found to exist in the textile material which has been so treated.

Among the deficiencies reported from the application of the compositions described in this patent is that the hand of the fabric tends to be too stitf and/or too soggy. With respect to this deficiency, its importance is magnified when one considers the adverse effect on sales which results from such a property. Thus, for example, fabric having a stilf and/or soggy hand is gener ally not acceptable for personal clothing; nor are they desirable for fabrics such as are employed for use as drapery material, slip covers and the like.

' Therefore, it is an object of the present invention to provide a thermoplastic composition which, when employed with a thermosetting aminoplast resinous material, may be applied to the cellulosic textile materials so as to impart a soft, full, dry hand to the treated fabric.

It is a further object to provide a thermoplastic composition, which, when employed in connection with a thermosetting aminoplast resinous material, will, in addition to providing the above enumerated etfects, enhance .the wash and wear qualities of the fabric so treated,

abrasion resistance, and will be durable to washing and dry cleaning as well as imparting other desirable properties thereto.

These and other objects and advantages will become apparent from the following description of the present invention set forth hereinbelow.

- According to the present invention, a process is provided for improving the properties of a cellulosic textile material-which comprises impregnating the said textile material with a combination of (l) a heat-curable aminoplast resinous material which is at least partially Watersoluble and (2) a substantially water-insoluble thermoplastic copolymer composition that is the product ofpolymerization of polymerizable monomers, said monomers consisting of a substantially azeotropic mixture of a stytime and alower alkyl ester of acrylic acid, wherein the 2,320,74 Patentedl viar, 22, 1960 alkyl group contains from 1 to 4 carbon atoms. The products of (1) and (2) are employed in weight ratios corresponding to from 2 to 4 parts of the former for each part of the latter. Thereafter, (1) is cured in situ in intimate contact with (2) to a substantially waterinsoluble state, the amount of the products of (1) and (2) applied to the textile material being such that the finished textile contains from between 2 /2 to 20% by weight based on the weight of the dry textile.

, By a substantially azeotropic mixture as the term is used herein, is meant one which will produce a copolymer substantially free of homopolymer, of either of the reacting components or monomers. The ratio of the reactants to produce such copolymers are based on the reactivity of the reacting components or monomers rather than on their molecular weights. Azeotropic mixtures and copolymers are defined more fully in the text Mechanism of Polymer Reaction by G. M. Burnett, copyright 1954, at page 249.

In the application of the mixed resinous composition, the thermosetting resinous material is used in an amount of from between 2 and 4:1 and preferably about 3.5 :.1 with respect to the thermoplastic azeotropic copolymer composition.

' In accordance with the present invention, the wateriusoluble thermoplastic compositions are employed in admixture with thermosetting aminoplast resins so as to apply from between 0.5% and 5% of the thermoplastic copolymer and preferably from between 1 and 3% thereof and from between 2 and 15% of the thermosetting aminoplast material and preferably from between 3.5 and'10% thereof, all percentages being based on the dry weight of the textile fabric. Thus, from between 2.5 and 20% of a suitable treating composition may be applied to the fabric, and preferably from between 4.5 and 13% is applied thereto.

The thermosetting aminoplast resin employed with the thermoplastic water-insoluble copolymer must be heat curable and at least partially water soluble. Included in the term aminoplast resin by way of example are melamine-formaldehyde reaction products, alkylated melamine-formaldehyde reaction products, guanamine and substituted guanamine-formaldehyde reaction products, including their alkylated derivatives, urea-formaldehyde reaction products, including cyclic ureas, such as ethylene urea, 1,2 and 1,3 propylene urea, and their alkylated derivatives and the like, employed either singly or in combination with one another. The methylol and alkylated methylol derivatives of these compounds may readily be prepared by methods well known to those skilled in the art.

Melamine-formaldehyde reaction products including their alkylated derivatives, are the preferred thermosetting aminoplast resin. These heat-curable reaction products may be used when at least partially soluble in water, though preferably they are substantially completely water soluble, either in the form of a true solution, or as a collodial dispersion. Examples of melamineformaldehyde reaction products that may be employed are those which contain one or more methylol groups,

more particularly, di, tri, tetra, penta, or hexamethylol omer, it is usually desirable to keep the reaction temperature from exceeding about 90 C.

The curable alkylated or alcohol reacted methylol melamine, more particularly, methylated polymethylol melamines, are especially suitable for: use in practicing the present invention. They may be prepared, for example, by eifecting reaction under acidic conditions, between a polymethylol melamine and a saturated aliphatic alcohol, containing from I to 4 carbon atoms in the ratio of 1 mole of the former to from 2 to 6 moles of the latter, depending upon the number of methylol groups in the melamine derivative, and the extent of etherification desired. The reaction is stopped before the. product becomes hydrophobic. Alkali is added in an amount at least sufficient to neutralize the reaction mass, after which the mass is dehydrated under vacuum. Advantageously, the methylated methylol melamine, more particularly, polymethoxymethyl melamine, is prepared in the manner such as is disclosed and claimed in U.S. Patent No. 2,529,856.

The thermoplastic copolymer latices of the present invention are produced by reacting in azeotropic quantities lower alkyl esters of acrylic acid wherein the alkyl group has from 1-4 carbon atoms and a styrene. Included in the formergroup are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl acrylates.

Among the styrenes which may be employed are styrene per se, ring-substituted vinyl toluenes, and side chain substituted styrenes. Examples of the latter two,

are chlorovinyl toluenes, methylvinyl toluenes (0. P).

cat-methyl styrene, u-ethyl styrene and the like.

' The thermoplastic copolymer employedin the present invention is produced by copolymerizing substantially an azeotropic mixture of a styrene and a lower alkyl ester of acrylic acid, in which the alkyl substituent contains from 1 to 4 carbon atoms by methods known to those skilled in the art, such as those generally described in. application, Serial No. 636,279, filed December 20, 1945,, which is now abandoned, and in detail by way of example hereinafter.

Azeotropic compositions of the suitable reactants within the meaning of the present invention can be each calculated from the reactivity ratio of a monomer pair, and then checked experimentally by usual analytical methods as is well known to those skilled in the art.

In this manner, it has been determined that the azeotropic mixture for the styrene-ethyl acrylate copolymer system is 80 parts of styrene and 20 parts of ethyl acrylate by weight in 100 parts of mixture. vWith respect to the styrene-butyl acrylate copolymer system, in a 100-- part. mixture, 57 parts are styrene and 43 parts are butyl acrylate which constitutes the azeotropic copolymer composition.

' In all of the thermoplastic copolymer compositions contemplated by the present invention, the styrene component is present by weight in amounts significantly in excess of 50% of the total copolymer composition. Thus, in the case of styrene and butyl acrylate, the latter is present as 43% by weight of the copolymer, while in. the case of styrene and ethyl acrylate the latter is present as 20% by weight of the mixture.

The components of the thermoplastic copolymer must be present in substantially azeotropic quantities, in order to produce optimum hand properties. Thus, in. the caseof the styrene-ethyl acrylate copolymer, a mixture of exactly 80 parts of the former to 20 parts of the latter is optimum, although an acceptable. copolymer mixture can vary slightly. Thus, for example, between 78 and 82.. parts of the former to 22 to 18 parts of the latter may be. used with acceptable results.

A, property of the thermoplastic copolymer of thepresent. invention isthat it is water insoluble and must be: applied as an emulsion. As used with a thermosetting resin, such as methylated methylol melamine, in which his frequently highly desirable to employ a metal salt as a curing catalyst therefor, coagulation of the theme plastic copolymer often results. This is particularly true when the metal salt catalyst is a salt of heavy metal ions such as magnesium chloride and zinc nitrate. The coagulating effect produced by a normal amount of such salt-curing catalyst may be overcome by using about 2% solids of a non-ionic surface active agent, based on the solids in the thermoplastic copolymer emulsion. This obviates the problem produced by coagulation, provided that the thermoplastic copolymer emulsion is added to the metal salt catalyst which usually is in admixture with the thermosetting resin. Any non-ionic agent is suitable here, as for example, those by the trade names of Triton X 100, the Pluronics, and Deceresol NI Conc. While the amount set forth hereinabove was expressed as 2% solids, the amount necessary is actually controlled by the amount of catalyst employed in the system.

As a process for producing the thermoplastic copolymers, a suitable vessel equipped with an agitator, reflux condenser, graduated dropping funnel, thermometer and heating means is provided, and in it are placed 350 parts of water and 2.5 parts of a non-ionic surface active. agent, such as Duponol C, the active component of which. has been identified as sodium lauryl sulfonate. The. temperature is then raised to about C. and 200 parts of an azeotropic monomer mixture, as for example, 20%.. (40 parts) of ethyl acrylate, and 80% parts). of

styrene by weight is added with continuous stirring, in 10-portion increments, a single portion beingv added.

every 15 minutes or so. After each feed period an aliquot addition of ammonium persulfate, initiator and a.

sodium bicarbonate buffer solution is added.

As an example of a suitable initiator composition, 0.268

part of ammonium persulfate dissolved in 50 parts of.

water functions in a highly desirable manner. As illustrative of the buffer solution, 0.3 part of sodium carbonate is usually sufficient to effect the necessary buffering action, where proportions of the magnitude set forth here inabove are employed.

After the addition is completed, the reaction mixture is refluxed with stirring for an additional 30 minutes. Thereafter, the residual monomers are removed by steam distillation, and preferably there is added 16 parts of a non-ionic wetting agent, as for example, Deceresol NI Couc., an alkyl aryl polyether alcohol, and finally the pH.' is adjusted to 8 with dilute ammonium hydroxide. The percentage of conversion from monomer mixture to polymer composition was approximately 97%.

Employing the general procedure outlined hereinabove,

water-insoluble thermoplastic copolymers within the meaning of the present invention may be prepared.

For the application of the thermoplastic copolymer and the thermosetting resin to cellulosic textile materials, a

pad bath is made up of a suitable thermosetting resin, as

for example, methylated methylol melamine, to which.

catalyst has been added, and thereafter the thermoplastic copolymer, preferably containing, in addition, a non-ionic surface active agent, is stirred in.

The amount of catalyst employed is usually from ire-- tween about 1 to 60% and preferably amounts of the.

order of between 2 and 25% based on the weight of the thermosetting resin which is applied to the fabric. Suitable catalysts within the meaning of the present inventionare ammonium salts such as ammonium chloride; amine salts. such as trimethylamine hydrochloride; mkanolamine salts such as triethauolamine hydrochloride; and metallic salts such as magnesiumchloride and zinc nitrate.

impregnation on the treatment of the fabric may be carried out in a number of different ways. The fabric may be impregnated, as for example, by soaking, immersion, dipping, spraying, padding, or the like, or other means known to those skilled in the art.

After the application of the resinous composition to the cellul'osic.v textile. fabricv to be, treated, it. may her-run through suitable squeeze rollers or other means whereby the desired amount of resin solids may be controlled, as well as excessive free moisture removed therefrom. Thereafter, the fabric may be dried until dry to the touch, as for example, at from 175 ii-250 F. and then cured,

:It will be observed that in all cases where the amounts of' ethyl acrylate and styrene employed in making the thermoplastic composition were not present in azeotropic amounts, the treated cotton was deficient in that the hand as for example, from 3 minutes at 350 F. to 0.5 minute 5 tended to be Soggy thillat 50 F. or the fabric may be dried and cured in a This is believed to be produced either by the presence single operation, as for example, for from 6 minutes at of homopolymer of an acrylate or homopolymer of a sty- 290 F. to 1.5 minutes at 450 F. rene. Thus when the copolymer composition is not azeo- The following examples are given primarily by way of tropic and homepelymer Of Styrene is Present, the m illustration in order that the present invention may be 10 t s t be t n and dry. When not n az otropie 601701)! more fully understood. No details therein should be coneempesitieil, and a homepolymef of 811 acrylflie is strued as limitations on the present invention except as P the hand tel-ids to be full, but 88) What is they appear in the appended claims. All parts and per- Sometimes termed a dead hand. centages are by weight unless otherwise designated. Among other advantages of the P Q Process 316 EXAMPLE 1 the durability to dry cleaning and the durabilityto washing of the finish applied. Table H, set forth hereinbelow, A piece of 80 x 80 cotton was padded through a compoints out these advantages by comparative test results. position consisting of a thermoplastic copolymer emulsion In determining durability of a particular finish .to dry containing 2 parts of an azeotropic copolymer composicleaning, tentative test method 25-52, at page 76 of the tion containing 80% styrene-% ethyl acrylate by 20 A.A.T.C.C. yearbook of 1955, was generally employed. weight and .04 parts of a non-ionic surface active agent In this method, swatches of the treated fabric are placed are mixed with an aqueous solution containing 5 parts of in a laundromcter in jars containing Varsol No. 2, a a water-soluble methylated methylol melamine and .6 Stoddard Solvent. The jars are run minutes at 80 F. part of magnesium chloride as a curing catalyst. and thereafter the samples are removed and centrifuged The treated material was then run through a squeeze 25 dry. The fabrics are then steam pressed, conditioned, and roll adapted to provide a 100% wet pick-up. Thereafter, evaluated for hand. (This test differs from 25-52 in that the fabric was dried 2 minutes at 225 F. and cured at 1 0 soap is employed. The soap is difiicult to remove 350 F. forl.5 minutes. from the fabric and could affect hand, and since dura- The following table is for purposes of registering combility to Washing is also determined, h Omission 0f the parisons of the properties of various thermoplasticcosoap is considered a valid deletion in this test.) polymer latices when used in conjunction with a thermo- In determining the durability to washing of the finish, setting resin and applied to cloth. In all cases, the'resins swatches of a treated fabric Washed an ag were as in Exa nple 1 so as to 5 arts of a Washer for minutes in Soap and a SOd3-; water-soluble heat-curable methylated methylol melamine f at The fabncs f then thoroughlyfmsed as the thermosetting resin and 2 parts of thermoplastic m water at 160 (three waslles) cenmfuged copolymer. The composition of the thermoplastic portion and Pressed on flat bed toner for 30 of the resinous compositions are set forth in columns 2 onds' The l were Foildltmned and evaluated and 3 of the table, according to their content of Styrene for hand. Th1s procedure is s1m1lar to the standard test and ethyl acrylatfi respectively and are generally pref method 36-54, page 56 of the 1955 A.A.T.C.C. yeard d 6n b V 40 book, except that larger swatches are employed, which pare as escn 6 er 1 a 0 necessitates an agitator wash instead of the laundrometer. Table l The wash employed also necessitated the modification of COMPARISON on THE EFFECT ONHAND ON 80x80 COTTON the Soap eencentrafiens- -In Table II, all of the applications were made in 8. Composition of 5% Melamine Resin +2 manner similar to that set forth in Example 1 herein- Thermoplastic Thermoplastic Oopolymer, above, Resin Nov 11%? Hand It will thus be seen according to Table II that where the resin treatment employed contains an azeotropic co- Stmne EA Soft Fun Dry polymer composition of a lower alkyl acrylate and styrene, the hand of the treated fabric is soft, full and dry. 10 90 ft full 7 S1v soggy The durability of the hand imparted by the azeotropic 50 50 stiff." full s ycopolymer and melamine resin is of the same order as 23 $1: 'g obtained with other thermoplastic copolymers and mel- 90 10 soft" thin. ivamine resin compositions. However, the appearance of fabric treated with the azeotropic copolymer and melalAzeotropic mixture mine resin is enhanced after washing compared to the Table II Composition of Thermoplastic 6% Melamine Resin +2% Thermoplastic Copolymer Applied to 80 x 80 copolymer, percent Cotton, Hand Resins Wash Ethyl Butyl and Styrene Acrylate Acrylate Initial Washed Dry Cleaning Wear Appear- 81166 10 90 so; F; so 50 so ST;F;SG 35 SO:F';SL 2o so; F;D 10 so; T;D so 20 so; '1; D 57 43 so; F; D SO; T; D

1 Legend: A eotropic compositions.

other combinations and may be said to have the. characteristics of a wash and wear finish.

Althoughithis invention has been described with particular reference to the treatment of cotton, specifically cotton fabrics, the treatment herein described may also be applied to other textiles which are composed substantially or mainly of cellulose or regenerated cellulose, for example, linen, hemp, jute, ramie, sisal, cellulose acetate rayons, cellulose acetate butyrate rayons, saponified acetate rayons, viscose rayons, cuprarnmouiurn rayorls, ethyl cellulose, and mixtures thereof, with each other or with cotton;

The term textile and textile material as used generally herein and in the appended claims, include within their meaning filaments, fibers, threads, yarns, twisted yarns, etc. as such, or in woven, non-woven or otherwise formed fabrics, sheets, cloths, and the like.

In addition to the essential components of the treating composition set forth hereinabove, namely, the thermoplastic copolymer, the thermosetting resin and the acid acting curing catalyst for the thermosetting resin, other additives which are not inconsistent and do not destroy the effect of the essential components of the present invention may be added therewith, as for example, softeners, antistatic agent, fillers, pigments, dyes, and the like, may be incorporated into the bath solution and applied simultaneously with the resin composition of the present invention. The impregnated cotton or other ce'llulosic textile .material of this invention is also resistant to shrinkage, as well as to wear and abrasion. The finish is durable and is not removed by washing in water and, in addition, is durable to dry cleaning, as noted in Table 11 above. The hand may be varied slightly, for example, by varying the kind and amount of thermoplastic modifier employed and/or the kind and amount of thermosetting resin within the limits set forth hereinabove.

"We claim:

' '1. .A process of improvingthe properties of cellulosic textile material which comprises impregnating the said textile material by imparting a soft, full, dry hand thereto, which is durable to dry cleaning and laundering, with a combination of (1) a partially water-soluble heat-curable synthetic aminoplast resin and (2) a substantially water-insoluble thermoplastic copolymer composition, the product of polymerization of polymerizable monomers, said polymerizable monomers consisting of an azeotropic mixture of a styrene and a lower alkyl ester of acrylic a'cidfwherein the styrene is present in an amount by weight in excess of 50% of the copolymer composition, and wherein the alkyl group contains from 1 to 4 carbon atoms, the products of 1) and (2) being employed in Weight ratios corresponding to from 2 to 4 parts of the former for each part of the latter, and curing in situ (l) in intimate contact with (2) to a substantially waterinsoluble state, the amount of the product of (l) and (2) applied to said textile material being such that the finished textile contains from 2.5 to 20% by weight oithedry textile material.

' 2. A process of improving the properties of cellulosic textile material which comprises impregnating the said textile material by imparting a soft, full, dry hand thereto, which is durable to dry cleaning and laundering, with assists a combination of (1) a partially watensoluble heat-curable reaction product of ingredients comprising melamine and formaldehyde and (2) a substantially waterinsoluble thermoplastic copolymer composition, the prodnot of polymerization of polymerizable monomers, said polymerizable monomers consisting of an azeotropic mixture of a styrene and a lower alkyl ester of acrylic acid, wherein the styrene is present in an amount by weight in excess of 50% of the copolymer composition, and wherein the alkyl group contains from 1 to 4 carbon atoms, the products of (l) and (2) being employed in weight ratios corresponding to from 2 to 4 parts of the former for each part of the latter, and curing in situ (1) in intimate contact with (2) to a substantially water-insoluble state, the amount of the product of (1) and (2) applied to said textile material being such that the finished textile contains from 2.5 to 20% by weight of the dry textile material.

3. A process according to claim 2 wherein the azeotropic thermoplastic copolymer is comprised of styrene and ethyl acrylate.

4. A process according to claim 2 wherein the azeotropic thermoplastic copolymer is comprised of styrene and butyl acrylate.

5. A- process according to claim 2 wherein the azeotropic thermoplastic copolymer is comprised of methylvinyl toluene and ethyl acrylate.

6. A process according to claim 2 wherein the azeotropic thermoplastic copolymer is comprised of methylvinyl toluene and butyl acrylate.

'7. A process according to claim 2 wherein the weight ratio between the products of (1) and (2) is 3.5 parts of the former to 1 part of the latter, and wherein the amount of the products of (1) and (2) applied to the textile material is from between 4.5 and 13% based on the weight of the dry textile material.

8. A cellulosic fabric material having a soft, full, dry hand which is durable to dry cleaning and laundering, which is impregnated with from 2 /2 to 20% by weight of the dry fabric material of a combination of 1) a substantially water-insoluble cured product which prior to curing is an at least partially water-soluble curable synthetic aminoplast resin and (2) an azeotropic thermoplastic copolymer composition that is the product of polymerization of polymerizable monomers consisting of an azeotropic mixture of a styrene and a lower alkyl ester of acrylic acid, wherein the styrene is present in an amount by weight in excess of 50% of the copolymer composition, and wherein the alkyl group contains from 1 to 4 carbon atoms and in which the products of (1) and (2) have been employed in weight ratios corresponding to from 2 to 4 parts of the former for 1 part of the latter,

. and in which (1) has been cured in situ in intimate con tact with (2) to said substantially water insoluble state.

References Cited in the file of this patent UNITED STATES PATENTS 2,054,131 Kollek Sept. 15, 1936 2,123,599 F-ikentscher et al July 12, 1938 2,140,048 Fikentscher et al Dec. 13, 1938 2,563,898 Wilson et a1 Aug. 14, 1951 2,823,142 Sumner et a1. Feb. 11, 1958 

1. A PROCESS OF IMPROVING THE PROPERTIES OF CELLULOSIC TEXTILE MATERIAL WHICH COMPRISES IMPREGNATING THE SAID TEXTILE MATERIAL BY IMPARTING A SOFR, FULL, DRY HAND THERETO, WHICH IS DURABLE TO DRY CLEANING AND LAUNDERING, WITH A COMBINATION OF (1) A PLURALITY WATER-SOLUBLE HEAT-CURABLE SYNTHETIC AMINOPLAST RESIN AND (2) A SUBSTANTIALLY WATER-INSOLUBLE THERMOPLASTIC COPOLYMER COMPOSITION, THE PRODUCT OF POLYMERIZATION OF POLYMERIZABLE MONOMERS, SAID POLYMERIZABLE MONOMERS CONSISTING OF AN AZEOTROPIC MIXTURE OF A STYRENE AND A LOWER ALKYL ESTER OF ACRYLIC ACID, WHEREIN THE STYRENE IS PRESENT IN AN AMOUNT BY WEIGHT IN EXCESS OF 50% OF THE COPOLYMER COMPOSITION, AND WHEREIN THE ALKYL GROUP CONTAINS FROM 1 TO 4 CARBON ATOMS, THE PRODUCTS OF (1) AND (2) BEING EMPLOYED IN WEIGHT RATIOS CORRESPONDING TO FORM 2 TO 4 PARTS OF THE FORMER FOR EACH PART OF THE LATTER, AND CURING IN SITU (1) IN INTIMATE CONTACT WITH (2) TO AOSUBSTANTIALLY WATERINSOLUBLE STATE, THE AMOUNT OF THE PRODUCT OF (1) AND (2) APPLIED TO SAID TEXTILE MATERIAL BEING SUCH THAT THE FINISHED TEXTILE CONTAINS FROM 2.5 TO 20% BY WEIGHT OF THE DRY TEXTILE MATERIAL. 